JP2009286350A - Control device for electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an electric power steering device easily tuned and stabilizing vehicle actions when moving a vehicle backward. <P>SOLUTION: The control device for the electric power steering device is provided with: a steering auxiliary command value computing section for computing a steering auxiliary command value based on the steering torque of the vehicle; a converging control part for inputting the angular velocity of a motor and outputting a converging signal; a current command value computing section for subtracting the converging signal from the steering auxiliary command value and computing a current command value corresponding to the phase number of the motor based on the steering auxiliary command value which is the subtracted result; a current control part for computing a voltage command value based on the current command value computed in the current command value computing section; and a motor driving part for driving the motor based on the voltage command value computed in the current control part. The control device thus giving assist force by the motor to a steering system is provided with a function of changing a gain of the converging signal between the forward time and reverse time of the vehicle. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for an electric power steering device mounted on a vehicle, and more particularly, it is possible to change the gain of a convergence signal for improving the yaw convergence of the vehicle when the vehicle moves forward and backward, The present invention relates to a control device for an electric power steering device with improved stability.

  An electric power steering device that applies an assisting force (steering assisting force) to a steering device of a vehicle by a rotational force of a motor, a steering shaft or a rack shaft by a transmission mechanism such as a gear or a belt via a reduction gear. An auxiliary force (assist force) is applied to the.

  A general configuration example of such an electric power steering apparatus will be described with reference to FIG. A column shaft 2 of the steering wheel (handle) 1 is coupled to a tie rod 6 of a steered wheel via a reduction gear 3, universal joints 4A and 4B, and a pinion rack mechanism 5. The column shaft 2 is provided with a torque sensor 10 that detects the steering torque of the steering wheel 1, and a motor 20 that assists the steering force of the steering wheel 1 is connected to the column shaft 2 via the reduction gear 3. Yes. The control unit 100 that controls the electric power steering apparatus is supplied with electric power from the battery 14 and also receives an ignition key signal via the ignition key 11. The control unit 100 receives the steering torque T from the torque sensor 10 and the control unit 100. The vehicle speed V detected by the vehicle speed sensor 12 is inputted, the steering assist command value I of the assist command is calculated based on the steering torque T and the vehicle speed V, and supplied to the motor 20 based on the calculated steering assist command value I. To control the current.

  An example of the configuration of the control device of the electric power steering apparatus configured as described above will be described with reference to FIG.

  The steering torque T from the torque sensor 10 and the vehicle speed V from the vehicle speed sensor 12 are input to the steering assist command value calculation unit 111 that constitutes the torque system 110, and the steering assist command value calculated by the steering assist command value calculation unit 111. Ia is phase-compensated by the phase compensation unit 112, and the steering assist command value Ib phase-compensated by the phase compensation unit 112 is input to the addition unit 107A. Further, the steering torque T is also input to the differentiating unit 113 constituting the torque system 110, and the differentially compensated steering torque Ta is input to the adding unit 107A.

  A compensation signal CM2 is also input to the adding unit 107A, and a current command value calculating unit 101 that calculates a current command value Id corresponding to the number of phases of the motor 20 by the steering assist command value Ic that is the addition result of the adding unit 107A. Is input. The current command value Id is input to the subtraction unit 121 constituting the current control system 120, and the motor current Im detected by the motor current detection unit 125 is fed back to the subtraction unit 121. The current command value Id and the motor current The deviation from Im (= Id−Im) is input to the PI control unit 122 of proportional integral control, and the current command value subjected to PI control is input to the PWM control unit 123 of pulse width control to become the voltage command value Ve. The motor 20 is driven via the inverter 124 by the command value Ve.

  A rotation sensor 21 such as a resolver is attached to the motor 20. An angular velocity calculation unit 102 that inputs a signal from the rotation sensor 21 calculates an angular velocity ω of the motor 20. The angular velocity ω is calculated by the angular acceleration calculation unit 103 and the convergence control. Input to the unit 104 and the SAT estimation unit 106. The convergence control unit 104 applies a brake to the operation that the steering wheel 1 swings in order to improve the yaw convergence of the vehicle, and specifically, the angular velocity ω output from the angular velocity calculation unit 102. Is input to output a convergence signal N2 for improving the convergence of the yaw of the vehicle.

The angular acceleration ω ^* calculated by the angular acceleration calculation unit 103 is input to the inertia compensation unit 105 and the SAT estimation unit 106, and the steering torque T and the steering assist command value Ib are also input to the SAT estimation unit 106. The inertia compensation unit 105 assists the force equivalent to the force generated by the inertia of the steering system, and prevents deterioration of the feeling of inertia or control responsiveness.

On the other hand, the SAT estimated value SAT ^* estimated by the SAT estimation unit 106 is fed back to the subtraction unit 107C, subtracted from the inertia signal N1 from the inertia compensation unit 105 by the subtraction unit 107C, and the subtraction result is the compensation signal CM1. Is input to the subtractor 107B. The convergence signal N2 from the convergence control unit 104 is also fed back to the subtraction unit 107B, the subtraction unit 107B subtracts the convergence signal N2 from the compensation signal CM1, and the subtraction result compensation signal CM2 is input to the addition unit 107A. Has been. The motor 20 is driven and controlled by the steering assist command value Ic compensated or corrected as described above.
JP 2002-369565 A

  A control device for a conventional electric power steering device is, for example, a control device for an electric power steering device disclosed in Patent Document 1, which feeds back a SAT value obtained by a SAT feedback unit to a steering assist command value through a feedback filter, Since the compensation amount is corrected according to the vehicle behavior when the vehicle moves forward, the driver can perform an appropriate steering wheel operation (steering wheel operation).

  However, the control device disclosed in Patent Document 1 does not take into consideration the reverse operation of the vehicle, and has a problem that the vehicle behavior becomes unstable when the vehicle is moving backward.

  The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a control device for an electric power steering device that is easy to tune and has stable vehicle behavior even when the vehicle is moving backward.

  The present invention provides a steering assist command value calculation unit that calculates a steering assist command value based on the steering torque of the vehicle, and outputs a convergence signal for improving the yaw convergence of the vehicle, using the angular velocity of the motor as an input. The convergence assist signal output from the convergence control unit is subtracted from the steering assist command value calculated by the convergence control unit and the steering assist command value calculation unit. A current command value calculation unit that calculates a current command value that matches the number of phases of the motor, and a current control unit that calculates a voltage command value based on the current command value calculated by the current command value calculation unit And a motor drive unit that drives the motor based on the voltage command value calculated by the current control unit, and is configured to apply an assist force by the motor to a steering system. Relates to a control system of the ring device, the object of the present invention are achieved by providing a function of changing the gain of the convergence signal in the time backward at the time of forward movement of the vehicle.

  Further, the object of the present invention is to increase the gain of the convergence signal when the vehicle moves backward as compared to when the vehicle moves forward, or to increase the gain of the convergence signal. This is achieved more effectively by changing according to the reverse speed.

  According to the control device for the electric power steering device according to the present invention, the gain of the convergence signal for improving the convergence of the yaw of the vehicle can be varied between when the vehicle moves forward and when the vehicle moves backward, and the gain is controlled. Since the sexuality signal is added to the steering assist command value, tuning is easy, and the vehicle behavior is stabilized even when the vehicle is moving backward.

  In the control device for the electric power steering device according to the present invention, the convergence parameter for improving the yaw convergence of the vehicle is obtained by having the gain parameter of the convergence control separately when the vehicle is moving forward and when the vehicle is moving backward. The gain of the signal is varied between when the vehicle moves forward and when the vehicle moves forward, and the gain-controlled convergence signal is subtracted from the steering assist command value, and the motor is driven based on the steering assist command value that is the subtraction result. I am doing so. That is, when the vehicle moves backward, the gain of the convergence signal output from the convergence control unit is increased compared to when the vehicle moves forward. For this reason, the vehicle behavior is stable both when the vehicle moves forward and when the vehicle moves backward.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows a configuration example of a control device for an electric power steering apparatus according to the present invention corresponding to FIG. 4. In the present invention, the convergence of the yaw of the vehicle output from the convergence control unit 104 is improved. The converging signal N2 to be fed is fed back to the subtraction unit 107B via the gain unit 130 with variable gain K. And the gain K of the gain part 130 is varied by the vehicle reverse signal B from the transmission part of a vehicle or CAN (Control Area Network). The gain unit 130 is switched so that the gain K is decreased when the vehicle does not receive the vehicle reverse signal B when the vehicle is moving forward or is stopped, and the gain K is increased when the vehicle is reverse when the vehicle reverse signal B is input. . Other components in FIG. 1 and their operations are the same as those in FIG.

  As shown in FIG. 2, the characteristic of the gain unit 130 is a constant gain AK that changes stepwise according to the forward vehicle speed when the vehicle moves forward, and is larger than the gain AK when the vehicle moves backward. The gain BK changes and becomes constant. Therefore, when the vehicle moves backward, the convergence signal N2 is fed back to the subtractor 107B with a larger gain than when the vehicle moves forward, so that the vehicle behavior is stabilized even when the vehicle moves backward.

  The present invention is applicable not only to column-type and pinion-type electric power steering apparatuses, but also to rack-assisted electric power steering apparatuses.

It is a block diagram which shows the structural example of the control apparatus of the electric power steering apparatus based on this invention. It is a figure which shows the example of a characteristic of the gain part which concerns on this invention. It is a general block diagram of the conventional electric power steering device. It is a block diagram which shows an example of the control apparatus of the conventional electric power steering apparatus.

Explanation of symbols

1 Steering wheel (handle)
3 Reduction gear 10 Torque sensor 12 Vehicle speed sensor 14 Battery 20 Motor 21 Rotation sensor 100 Control unit 101 Current command value calculation unit 102 Angular velocity calculation unit 103 Angular acceleration calculation unit 104 Convergence control unit 105 Inertial compensation unit 106 SAT estimation unit 107A Adder 107B, 107C Subtraction unit 110 Torque system 111 Steering assist command value calculation unit 112 Phase compensation unit 113 Differentiation unit 120 Current control system 121 Subtraction unit 122 PI control unit 123 PWM control unit 124 Inverter (motor)
125 Motor current detection unit 130 Gain unit

Claims (3)

A steering assist command value calculator for calculating a steering assist command value based on the steering torque of the vehicle;
A convergence control unit that outputs a convergence signal for improving the yaw convergence of the vehicle, using the angular velocity of the motor as an input;
The convergence signal outputted from the convergence control unit is subtracted from the steering assistance command value calculated by the steering assistance command value calculation unit, and the phase number of the motor is based on the steering assistance command value which is the subtraction result. A current command value calculation unit that calculates a current command value suitable for
A current control unit that calculates a voltage command value based on the current command value calculated by the current command value calculation unit;
A motor drive unit that drives the motor based on the voltage command value calculated by the current control unit,
In the control device for the electric power steering device adapted to apply the assist force by the motor to the steering system,
A control device for an electric power steering apparatus, comprising a function of changing a gain of the convergence signal between forward and reverse of the vehicle.   2. The control device for an electric power steering apparatus according to claim 1, wherein when the vehicle moves backward, the gain of the convergence signal is increased as compared to when the vehicle moves forward.   The control device for an electric power steering apparatus according to claim 2, wherein a gain of the convergence signal is changed in accordance with a reverse speed of the vehicle.

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